Hydrodynamic nozzles of this general type are previously known. In U.S. Pat. No. 4,756,324 B1 and U.S. Pat. No. 5,992,432 B1, e.g., different hydrodynamic nozzles readable on the preamble of claim 1 are shown. These known nozzles both comprise a substantially homogenous nozzle body with a rotationally symmetric exterior. Embodiments include a channel extending centrally through the nozzle body to mouth in that end of the nozzle which is opposite from the end in which rinsing water is supplied to the nozzle. The channel is connected to the rinsing water intake and arranged for discharge of rinsing water in the direction of movement as the nozzle travels towards the far end of the pipe to be cleaned.
Another hydrodynamic nozzle is previously known from U.S. Pat. No. 3,814,330 B1, operating in a similar way. This nozzle however differs from the above mentioned nozzles in that, inter alia, it has a section-wise substantially cruciform nozzle body. From a central portion to an imaginary periphery connecting the outer ends of adjacent arms, the nozzle body is outwards open between the arms of the cross. This way there is formed a cross-section having substantially quarter-circular passages along the nozzle body, which passages are outwardly non-restricted in the radial direction. The purpose of the passages is explained to allow for transport of detached material along the nozzle body as the nozzle travels towards the far end of the pipe to be cleaned.
The transport of detached material in the operative direction is a power consuming work that employs a portion of the energy supplied with the rinsing water, and thus also consumes a portion of the cleaning capacity of the nozzle. This problem is not discussed or solved in known designs of hydrodynamic nozzles.